It has long been observed that married persons experience more favorable mortality than nonmarried persons. Possible explanations for mortality differentials by marital status include hypotheses regarding errors in the data, hypotheses related to the selection of persons into and out of marital states, and hypotheses concerning environmental and behavioral factors associated with marital states. The primary objective of the proposed research is to gain a better understanding of the relationship between the risk of mortality and marital status, from existing data. The first stage of our proposed research will involve calculations of mortality differentials by age, sex, and race for the U.S. in 1980 and an examination of the role of reporting errors in explaining these differentials. The roles of marriage selection and marriage protection will then be explored in several ways. First, the causes of death which account for observed mortality differentials by marital status will be explored. Second, based on high quality data from developed countries, relationships between proportions single (or divorced) and the excess mortality of the single (or divorced) across countries will be investigated. Third, a similar analysis will be carried out for different cohorts within individual countries, and the relationships will be examined from age, period, and cohort perspectives. Finally, a multivariate hazards model of mortality that controls simultaneously for several factors will be estimated, and the significance of interactions among these factors will be investigated.